An imbalance of electric charges within or on the surface of a material creates static electricity. This charge imbalance is most commonly observed as resulting from what is known as the triboelectric effect, also referred to as triboelectric charging. Tribolectric charging causes materials with weakly bound electrons to lose electrons through friction to materials with sparsely filled outer shells, resulting in one material becoming positively charged and the other negatively charged. Electrostatic discharge (ESD) is the sudden flow of electricity between two objects caused by contact. In everyday life, a common example of triboelectric charging occurs when someone walks across a floor creating a buildup of static electricity, and a common example of ESD occurs when that person touches a light switch or other conductive material, sometimes resulting in a small spark.
The spark created in the example above is typically harmless, and sometimes even imperceptible to human beings, but can potentially be very damaging to electronic devices and components. The example above of a person walking across a floor and touching a conductive material is just one of many examples of how static electricity can buildup and result in ESD that if brought into contact with electrical devices can potentially cause damage to the electrical device or electrical components within the device.